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To harness the potential of a quantum computer, quantum information must be protected against error by encoding it into a logical state that is suitable for quantum error correction. The Gottesman-KitaevPreskill (GKP) qubit is a promising candidate because the required multiqubit operations are readily available at optical frequency. To date, however, GKP qubits have been demonstrated only at mechanical and microwave frequencies. We realized a GKP state in propagating light at telecommunication wavelength and verified it through homodyne measurements without loss corrections. The generation is based on interference of cat states, followed by homodyne measurements. Our final states exhibit nonclassicality and non-Gaussianity, including the trident shape of faint instances of GKP states. Improvements toward brighter, multipeaked GKP qubits will be the basis for quantum computation with light. [ABSTRACT FROM AUTHOR]

The article discusses Australia's significant investment in PsiQuantum to build a large-scale quantum computing facility in Brisbane, Queensland, focusing on the country's gamble on photon-based quantum computing technology. Topics include the advantages of photon-based qubits over traditional approaches, the challenges and advancements in scaling up this technology, and the potential impact of Australia's investment on its quantum computing ecosystem and workforce development.

Quantum walks are the quantum mechanical analog of classical random walks and an extremely powerful tool in quantum simulations, quantum search algorithms, and even for universal quantum computing. In our work, we have designed and fabricated an 8-by-8 two-dimensional square superconducting qubit array composed of 62 functional qubits. We used this device to demonstrate high-fidelity single- and two-particle quantum walks. Furthermore, with the high programmability of the quantum processor, we implemented a Mach-Zehnder interferometer where the quantum walker coherently traverses in two paths before interfering and exiting. By tuning the disorders on the evolution paths, we observed interference fringes with single and double walkers. Our work is a milestone in the field, bringing future larger-scale quantum applications closer to realization for noisy intermediate-scale quantum processors. [ABSTRACT FROM AUTHOR]

The article focuses on a new quantum algorithm proposed by computer scientist Oded Regev, which could potentially be more efficient than Peter Shor's 30-year-old algorithm for factoring large numbers, a critical task for hacking internet encryption. Topics discussed include the multidimensional nature of Regev's algorithm, its potential to reduce the number of gates required, and the drawbacks associated with increased memory requirements, which raise questions about its practicality.

A key step toward demonstrating a quantum system that can address difficult problems in physics and chemistry will be performing a computation beyond the capabilities of any classical computer, thus achieving so-called quantum supremacy. In this study, we used nine superconducting qubits to demonstrate a promising path toward quantum supremacy. By individually tuning the qubit parameters, we were able to generate thousands of distinct Hamiltonian evolutions and probe the output probabilities. The measured probabilities obey a universal distribution, consistent with uniformly sampling the full Hilbert space. As the number of qubits increases, the system continues to explore the exponentially growing number of states. Extending these results to a system of 50 qubits has the potential to address scientific questions that are beyond the capabilities of any classical computer. [ABSTRACT FROM AUTHOR]

The article presents insights on the increasing popularity of quantum computing. Topics discussed include the efforts of small business enterprises and international businesses to harness quantum mechanics for use in quantum computers, the difference between a classical computer and a quantum computer, and the negative characteristic of quantum superpositions. Also mentioned are the quantum bits or qubits being experimented by companies which include trapped ions and superconducting loops.

The construction of a quantum computer remains a fundamental scientific and technological challenge because of the influence of unavoidable noise. Quantum states and operations can be protected from errors through the use of protocols for quantum computing with faulty components. We present a quantum error-correcting code in which one qubit is encoded in entangled states distributed over seven trapped-ion qubits. The code can detect one bit flip error, one phase flip error, or a combined error of both, regardless on which of the qubits they occur. We applied sequences of gate operations on the encoded qubit to explore its computational capabilities. This seven-qubit code represents a fully functional instance of a topologically encoded qubit, or color code, and opens a route toward fault-tolerant quantum computing. [ABSTRACT FROM AUTHOR]

The article discusses research on the use of vibrations to control quantum circuits. Topics include the use of qubits in quantum computing, differences between a microwave resonator and a mechanical or acoustic resonator, and the use of surface acoustic waves (SAWs). The possible significance of quantum acoustics is addressed.

The article discusses a quantum computer from quantum computing company D-Wave Systems, called the D-Wave computer. Topics include tests of a D-Wave computer owned by aerospace firm Lockheed Martin by physicist Matthias Troyer at the Swiss Federal Institute of Technology in Zurich and physicist Daniel Lidar at the University of Southern California in Los Angeles that found it computed no faster than conventional computers, D-Wave’s quantum annealing technique, and qubits.